Description:FIELD OF THE INVENTION
The present invention relates to a method of manufacturing bio-based synthetic leather in the form of a multi-layered material substantially from natural fibres that is suitable for a variety of applications. More particularly the present invention relates to a method of making a non-woven stack material with a fabric backing that can be used as a substitute for conventional animal leather.
BACKGROUND OF THE INVENTION
Leather is used in many industries like furniture, fashion automobile, etc. However, the production of the leather leaves behind enormous environment footprint by increase in greenhouse gases and causing the air and water pollution due to manufacturing procedures like tanning. The environmental impact of the production processes, renewability of resources, and damage inflicted on ecosystems warrant health and sustainability concerns of consumers.
The leather production not only affects environment but its manufacturing causes cruelty against the animals. In order to overcome the increased demand of leather and also to mitigate the hazardous effect on the environment, the technology of synthetic leather materials have been developed and widely used as an alternative to animal leather. However, currently available synthetic leathers are mostly made from unsustainable plastic (such as petro-chemically derived plastic). Such synthetic leather is not biodegradable, which places a burden on the environment. Also, these synthetic leathers fail to provide the qualities of animal leather that consumers desire, so many consumers tend to still prefer animal leather, especially for premium consumer products.
Thus, there is need of an improved technology for producing synthetic leather to achieve higher sustainability and better performance while maintaining a premium leather look and can be used as substitute of animal leather. An alternative textile to the conventional animal leather must include comparable characteristics in terms of water resistance, tensile strength, and physical appeal.
Therefore, there is a need to develop an alternative production process to obtain a plant-based biodegradable leather material with an improved tensile strength, appearance, and further advantageous material characteristics for its use as a textile material and as a substitute to animal leather.
OBJECT OF THE INVENTION
The primary object of the present invention is to provide a plant-based biodegradable leather which is durable, comfortable, affordable and sustainable in nature.
Another object of the present invention is to provide a plant-based biodegradable leather which exhibits leather like properties and appearance and can be used as substitute of animal leather.
A further object of the present invention is to provide a method of making plant-based biodegradable leather from recycled and plant-based raw material resources.
SUMMARY OF THE INVENTION
The present invention discloses a process of making plant-based biodegradable leather made from multiple layers comprising a handmade paper made from recycled raw materials, a cork fabric made from cork fiber and textile backing attached together in a multi-layer stacking by a plant-based adhesive derived from cellulose.
The process of making a leather begins with making of a hand-made paper from a plant-based raw materials. The steps include sorting, dusting and sieving of raw materials to remove the dust and dirt particles, chopping of raw material to obtain equal sized raw material, beating of raw material and water mixture with harmless chemicals in a Hollander beater machine to obtain a pulp, making a paper sheets using dipping or lifting method, couching of paper sheets by transferring the wet paper on a muslin cloth or felt sheet to form a stack of interleaved paper sheets, pressing of paper sheets with hydraulic press to remove excess of water to improve the physical properties of the paper and faster drying, cleaning and sizing of paper sheets by covered them with a layer of starch based coatings of starch or latex, polyvinyl alcohol (PVA) or carboxymethyl cellulose (CMC) or alike to improve the quality of the paper and prevent feathering out, calendaring of sheets by placing them between a metallic plates and then passing through spring-loaded rollers in a calendaring machine to make the paper smooth and glossy, cutting of paper according to the required size.
The preparation of the cork fabric using phellem layer of the bark tissue of oak tree backed with a natural fabric layer configured to provide support to the thin layer of cork.
The preparation of plant-based methyl cellulose adhesive by methylation of paper pulp wherein the said methyl cellulose is combined with water in a 3% solution: 970 ml of water to 30 g of methyl.
The natural adhesive can also be prepared using mixture of the flour or starch and water with added sugar or white glue to improve the stickiness. The consistency of the glue depends on starch/flour type or brand used in making of glue. In order to remove any lumps and to obtain smooth paste the mixture is strained using thin sieve or mesh cloth.
The bonding of layers by application of the plant-based adhesive layer onto a surface of the backing of hand-made paper layer and on surface of the cork fabric layer, respectively, and pressure is applied on one of the backing layer of the cork fabric layer to press the backing of hand-made paper layer.
The biodegradable leather is applied with aqueous coating to make it durable, water-resistant and give it a finishing appearance. The aqueous coating can be selected from a gloss, matte, satin, soft-touch or alike depending on application and use of the biodegradable leather.
The biodegradable leather is embossed wherein the leather is bonded with foam and lining on the back before embossing so that the embossed pattern sits neatly and retains its depth. The fabric is placed in the embossing machine loaded with embossing die and a set desired tension. It is necessary to determine variables such as pulp consistency, sheet thickness, number of felts, amount of pressure, etc. before embossing the natural plant-based leather. The leather is screen printed and/or ultraviolet printed with the desired designs.
The plant-based biodegradable leather has its application in preparation of purses, wallets, belts, shoes, watch straps, backpacks, suitcases, diaries and journals, bags, motorcycle saddlebags, briefcases or alike.
DESCRIPTION OF THE DRAWINGS:
Figure 1 illustrates a cross sectional view of multilayered biodegradable leather of the present invention.
Figure 2 illustrates a handmade paper layer used in the making of biodegradable leather of the present invention.
Figure 3 illustrates a cork fabric layer made using cork fiber and fabric backing used in the making of biodegradable leather of the present invention.
Figure 4 illustrates a biodegradable leather of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The following detailed description sets forth to provide a more thorough understanding of the present invention.
The present invention discloses a process of making a plant-based biodegradable leather resulting in textile having physical properties comparable to conventional animal leather, for example, physical appearance, water resistance, and tensile strength. The present disclosure seeks to address the problems of adverse environmental impact of damage to ecosystem integrity, and poor waste utilization, posed by conventional leather production and processing. The process disclosed in the present invention generates no wastage during the extraction, processing, or production.
The biodegradable plant-based leather of the present invention comprises of a handmade paper (10) made from recycled raw materials, a cork fabric made from cork fiber (20) and fabric backing (30) attached together in a multi-layer stacking by a plant-based adhesive (40) derived from cellulose.
The following description of embodiments, numerous specific details are set forth in order to provide more thorough understanding. The embodiments relate to a plant-based bio-degradable leather and a method of forming the plant-based biodegradable leather.
The method involves the steps:
Step 1: Making of a hand-made paper (30)
The first step involves making of hand-made paper from recycled raw materials as one of the layers of the leather of the present invention. The raw material used for the preparation hand-made paper is selected from but not limited to the materials like paddy, wheat straw, used hosiery cuttings, jute, scrap paper-cardboards, old newspapers, bagasse, bamboo, banana fiber, coffee husk, coconut husk, lemon grass, corn husk, tea waste or alike.
Process of making hand-made paper comprises steps:
A. Sorting and dusting: The raw material is manually sorted and foreign material like buttons, plastic, synthetic fibres etc. are removed. The material is shaken vigorously with sieve to remove any dust and dirt particles.
B. Rag Chopping: The sorted and dusted raw material is chopped into pieces to obtain equal particle size.
C. Beating: The raw material is mixed with water and harmless chemicals and is introduced in a Hollander beater machine for beating to obtain a pulp. The machine consists of a trough, a drum and iron blades on the outer side of the said drum which beat the raw material into a pulp. The washing drum cleans the pulp and drains the dirty water. The consistency of the pulp determines the quality of the paper.
The hand-made paper sheets can be made in two ways:
i. Dipping Method: This method is used to make a fine and thin paper by diluting the pulp with water and then pouring it into a masonry trough or vat. The lifting mold made of mesh on a wooden frame is dipped into the trough, shaken evenly and lifted out with the pulp on it.
ii. Lifting Method: This method is used to make a regular paper and cardboard papers. A fixed quantity of pulp is poured evenly onto a mold, which is then clamped between two wooden deckles (frames) and then dipped into a water tank. The mold in then lifted using a lever mechanism that allows the excess water to drain away.
F. Couching: The wet paper is transferred onto a muslin cloth or felt sheet to form a stack of interleaved paper sheets.

G. Pressing: The excess of water from paper sheets is removed using hydraulic press. This process improves the physical properties, thickness of the paper and also helps in faster drying.

H. Drying: The paper sheets are subjected to solar drying to remove moisture content from paper. The coloured papers are dried in the shade to prevent the color fading.

I. Cleaning and Sizing: The paper sheets are cleaned to remove small particles of dirt and foreign matter manually using sharp instrument. The cleaned sheets are covered with a layer of starch-based coatings of starch or latex, polyvinyl alcohol (PVA) or carboxymethyl cellulose (CMC) to improve the quality of the paper and prevent feathering out. This process is called sizing. This can be done manually using a brush or by dipping the sheet into a vat containing sizing chemicals.

J. Calendaring: The sheets are then placed between metallic plates and passed through spring-loaded rollers in a calendaring machine. This makes the paper smooth and increases the gloss of the paper.

K. Cutting: The sheets are finally cut neatly according to the required size using a cutting equipment.

Step 2: Cork Fabric (20) Making Process
Preparation of cork fabric - a natural textile using plant fibres. The cork is harvested from a branch of an oak tree which is characterized with regrowth after every harvest. The phellem layer of bark tissue is used to make a versatile and impermeable fabric material as one of the layers of leather of present invention.
The process of preparing cork fabric is as below:

i. The phellem layer of bark tissue is used to make cork fabric, a versatile and impermeable material. The collected cork is boiled in water in huge tanks. This process requires the water several times to assure that all fungus and bacteria on the surface of the barks get killed to prevent formation of “corked wine” or irregular structure and color of cork. Boiling of cork is done in a controlled and closed environment to trap volatile substances by putting weights over the cork to keep it submerged in the boiling water. The boiling process further aids in flattening of the cork due to the heat and the weight of the cork stacked.

ii. The cork is put to rest and dry between three to four months. The dried cork dried pieces are tested and quality controlled to check any contamination or unusual changes before cutting them in a regular shapes of around 25 to 45 cm in size.

iii. The dense middle section of the cork is used to prepare the cork fabric. The cork pieces are then sliced into three layers and the middle layer is treated further for turning into a fabric.

iv. The middle layer is further sliced in layers of 0.3 to 0.4 mm to obtain a “traditional” look of the textile. The slices may also be colored first and cut into layers. The slices are then glued together by applying heat and then sliced again. The application of heat and the natural glue “resin” in the cork forms a strong bond between cork slices.

v. These thin slices are backed with woven or non-woven natural fabric (30) selected from cotton, polyester, poly-cotton using a natural and water-based glue to prevent breakage. The slices are layered at the edges of each piece to obtain a cork fabric.

vi. The cork fabric is then pressed and grinded to obtain a smooth textured cork fabric.

Step 3: Procedure to prepare plant-based adhesive (40):
The present invention employs a natural plant-based adhesive made from cellulose for gluing of layers of fabric and paper. The pulp generated through recycling process undergoes methylation process to form methyl cellulose. The said methyl cellulose is combined with water in a 3% solution:

In an embodiment, the natural adhesive can also be prepared using mixture of the flour or starch and water with added sugar or white glue to improve the stickiness. The consistency of the glue depends on starch/flour type or brand used in making of glue. In order to remove any lumps and to obtain smooth paste the mixture is strained using thin sieve or mesh cloth.

Step 4: Attachment of the hand-made paper (10) and cork fabric (30):
The natural glue or adhesive paste is applied liberally using a paint brush or gloved hands on the surface of the cork fabric before attachment of hand-made paper. The adhesive or glue adheres the surfaces of cork fabric, backed natural fabric & paper in a strong bond to form a biodegradable leather.
In some embodiments, the plant-based adhesive layer is applied onto a surface of the backing of hand-made paper layer and on surface of the cork fabric layer, respectively, and pressure is applied on one of the backing layer of the cork fabric layer to press the backing of hand-made paper layer.

Step 5: Aqueous Coating
The biodegradable leather is applied with an aqueous coating to make it durable, water-resistant and give it a finishing appearance.
The different types of aqueous coating include but not limited to a gloss, matte, satin, soft-touch or alike depending on application and use of the biodegradable leather.

Step 6: Embossing & Screen Printing
The leather is embossed first and then screen printed depending on its application.

1) Embossing: The leather is bonded with foam and lining on the back before embossing so that the embossed pattern sits neatly and retains its depth. In some embodiments a fabric may be glued to the back to prevent stretching and flattening of the embossed motif. The fabric is placed in the embossing machine loaded with embossing die and a set desired tension. It is necessary to determine sheet thickness, number of felts, amount of pressure, etc. before embossing the natural plant-based leather.
2) Screen Printing: The desired designs are printed on biodegradable leather using screen printing or UV printing.
i. Screen Printing: The screen printing uses fabric stretched tightly over a frame. The images are created by blocking parts of the screen with stencils created by hand-drawn or photographic techniques. The ink is forced through the open areas of the screen onto the fabric sheet.
ii. UV printing: The UV Printing is method of digital printing that utilizes Ultraviolet (UV) light to dry or cure the ink, adhesives, or coatings almost as soon as it hits the paper or any surface/material.

ADVANTAGES AND SIGNIFICANCE OF THE INVENTION

1. The process of manufacturing of biodegradable leather of the present invention does not produce waste during extraction, processing, or post-production.
2. There are no artificial additives, toxic tanning or finishing substances used during the processing or post-processing of material.
3. The produced leather is fully recyclable & biodegradable and therefore can be milled into new materials.
4. The manufacturing process is completely environment safe as it does not produce any toxic waste.
5. The biodegradable leather of the present invention is durable, comfortable, affordable, and sustainable.

The embodiments of the present invention provides application of the biodegradable leather in preparation of purses, wallets, belts, shoes, watch straps, backpacks, suitcases, diaries and journals, bags, motorcycle saddlebags, briefcases or alike applications.
Example:
The figure 1 illustrates a cross sectional view of the biodegradable leather comprising a hand-made paper layer made from plant-based raw material including waste materials like rags, used papers, etc. using afore-mentioned process. The cork fabric layer is prepared from bark of the oak tree. The thin slice of the cork is backed with the cotton fabric to prevent its breakage. The paper and the cork fabric are bonded together using a natural adhesive in multi-layered stack to form a biodegradable leather. The said leather is then is coated with aqueous coating, embossed to give it leather like finishing and appearance. The said leather can be used to make purses, wallets, bags, etc.
The above description is an illustrative description of the present invention, and the embodiments are not intended to limit the present invention, but to describe the present invention. Various modifications and variations will be possible without departing from the scope of the invention. , Claims:1. A plant based biodegradable leather comprising of;
a handmade paper (10) made from recycled raw materials;
a cork fabric made from cork fiber (20) extracted from oak tree;
a fabric (30) backing attached to the said cork fabric assembled in a multi-layer stacking bonded by a plant-based adhesive (40) derived from cellulose;
wherein the internal structure of each layer has regions of differing thickness, density and material properties.

2. The plant based biodegradable leather as claimed in claim 1, wherein the raw material includes paddy, wheat straw, used hosiery cuttings, jute, scrap paper-cardboards, old newspapers, bagasse, bamboo, banana fibre, coffee husk, coconut husk, lemon grass, corn husk, tea waste or alike waste material.

3. The plant based biodegradable leather as claimed in claim 1, wherein the said biodegradable leather can be used in preparation of purses, wallets, belts, shoes, watch straps, backpacks, suitcases, diaries and journals, bags, motorcycle saddlebags, briefcases or alike.

4. The plant based biodegradable leather as claimed in claim 1, wherein the said fabric may be woven or non-woven natural fabric selected from cotton, polyester, poly-cotton or alike.

5. A process of biodegradable leather comprising of steps:
a. preparing of hand-made paper from a plant-based raw material
i. sorting, dusting and sieving of raw material to remove dust and dirt particles;
ii. chopping of raw material to obtain equal sized raw material;
iii. beating of raw material and water mixture with harmless chemicals in a Hollander beater machine to obtain a pulp;
iv. making a paper sheets using dipping or lifting method;
v. couching of paper sheets by transferring the wet paper on a muslin cloth or felt sheet to form a stack of interleaved paper sheets;
vi. pressing of paper sheets with hydraulic press to remove excess of water to improve the physical properties of the paper and faster drying;
vii. drying of paper sheets;
viii. cleaning and sizing of paper sheets by covered with a layer of starch based coatings of starch, latex or polyvinyl alcohol (PVA) or carboxymethyl cellulose (CMC) to improve the quality of the paper and prevent feathering out;
ix. calendaring of sheets by placing them between a metallic plates and then passing through spring-loaded rollers in a calendaring machine to make the paper smooth and glossy;
x. cutting of paper according to the required size;

b. preparation of the cork fabric using phellem layer of the bark tissue with natural fabric layer being configured to provide support to the thin layer of cork form another layer of the biodegradable leather;
c. preparation of plant-based methyl cellulose adhesive by methylation of paper pulp;
d. bonding of layers by application of the plant-based adhesive layer onto a surface of the backing of hand-made paper layer and on surface of the cork fabric layer, respectively, and pressure is applied on one of the backing layer of the cork fabric layer to press the backing of hand-made paper layer;
e. application of the aqueous coating to biodegradable leather to make it durable, water-resistant and give it a finishing appearance;
f. embossing of biodegradable leather wherein the leather may be bonded with foam and lining on the back before embossing so that the embossed pattern sits neatly and retains its depth;
g. screen printing and/or ultraviolet printing of desired designs on the biodegradable leather.
6. The process of claim 1, wherein the aqueous coating can be selected from a gloss, matte, satin, soft-touch or alike depending on application and use of the biodegradable leather.
7. The process of claim 1, wherein the said methyl cellulose is combined with water in a 3% solution: 970 ml of water to 30 g of methyl.